1. Field of the Disclosure
The present disclosure relates to biopsy forceps compatible with endoscopic tools. More particularly, the present disclosure relates to biopsy forceps compatible with optical biopsy tools such that samples of the as-optically biopsied tissue may be retrieved for further analysis.
2. Description of the Related Art
A biopsy is a medical test involving the removal of cells or tissues for examination, referred to throughout as a mechanical biopsy. After extraction from a patient, the tissue is generally examined under a microscope by a pathologist, and may also be analyzed chemically. When an entire lump or suspicious area is removed, the procedure is called an excisional biopsy. When only a portion of tissue (e.g., a sample) is removed with preservation of the histological architecture of the tissue's cells, the procedure may be called an incisional biopsy or a core biopsy. When a sample of tissue or fluid is removed with a needle in such a way that cells are removed without preserving the histological architecture of the tissue cells, the procedure may be called a needle aspiration biopsy. Biopsies are generally performed for diagnosis and early detection of pathologies and are often used for follow-up of pathologies.
In the particular case of rigid or flexible endoscopy, either in pulmonology or in gastroenterology, incisional biopsies are typically performed with a forceps. A typical forceps 100 (e.g., as shown in FIG. 1) comprises an incisional device 101, (e.g., a pair of miniaturized jaws) which may be inserted into the patient's body to a region of interest through an accessory channel of an endoscope (not shown). The forceps may be actuated from outside of the patient's body by operation of handle 102. The biopsy may be performed by the endoscopist or his assistant under video control and observation from the endoscope. After the forceps is closed, and a sample is extracted from the tissue of interest, it may be retracted from the endoscope so that the sample may be retrieved and analyzed by a pathologist. Each time the forceps is used, a volume of tissue up to about a few cubic millimeters may be removed and the same forceps may be re-used during the same procedure. Conventionally, forceps may be used successively in an organ or in a single patient, but they may not be used in different patients (or, in certain instances, in different organs) to prevent cross-contamination. Therefore, forceps have historically been sold as disposable items.
For mechanical biopsies, an alternative to jaws 101 may be snares, as shown in FIG. 2. Biopsy snares permit grabbing structures with a sufficient vertical extension over the surface of the mucosa. Snares may be preferred for certain tangential biopsies, for example, polypectomies.
Additionally, an alternative to mechanical biopsies has recently developed. The new procedure consists of inserting an optical device (as opposed to a mechanical device) into the accessory channel of the endoscope 110 (e.g., as shown in FIG. 3) that is specifically designed to perform an optical analysis of the internal layers of the mucosa. For example, a fiber optic “microscope” (optical biopsy probe) 111 may be delivered to tissue from within an accessory channel of an endoscope to micro-analyze the area of investigation in-situ. Because these techniques, also called optical biopsies, are not invasive, they may be repeated ad libitum, and a much larger portion of the mucosa may be searched for areas of interest.
Even in view of the advantages of optical biopsies, mechanical biopsies may be preferred. The preference may result from the highly detailed analysis of an obtained sample that may be performed by the pathologist and because a much larger amount of histological data may exist. Therefore, the mechanical biopsy procedure is considered as a reference, or gold standard. However, a drawback to the “gold standard” is that at very early stages of a pathology the biopsy procedure may be conducted randomly or blindly. Such a practice may unfortunately lead to a large number of false negatives (i.e., situations were a pre-malignant or malignant condition is not detected).
In this context, optical biopsies may be envisioned as a preliminary and complementary procedure that may be used for identifications for subsequent mechanical biopsies. The combination of both techniques may not only reduce the number of false negatives (and consequently increase the overall accuracy of the biopsy process), but also may reduce the overall cost of diagnostic procedures.
A typical pair of biopsy forceps 100 is shown in FIG. 1. The forceps 100 comprise a pair of jaws 101 mounted at a distal end of a sheath 104 and a handle 102 is disposed at the proximal end of the sheath. Handle 102 may be connected to a wire 105 (see FIG. 6) that, through sheath 104, controls the opening or the closing of jaws 101. Jaws 101 may be a few millimeters in length and the sheath 104 may be, as is typical, a metallic coil that may be 2 to 3 meters long.
Various mechanisms exist to operate the jaws of the forceps with appropriate movements and amplitude and with a desirable amount of strength. Biopsy forceps currently available may be divided into one of two categories, levers or pantographs (e.g., FIG. 4) and pivots (e.g., FIG. 5). Both solutions work on the principle of two opposite and combined actions. Referring to FIG. 6, when an inner wire 105 pulls on the extremity of the pantograph or the pivot, while the outer sheath 104 pushes on the central articulation of the pantograph or on the jaws themselves, the jaws are closed.
Biopsy forceps may be equipped with different kinds of jaws (FIGS. 7A-7D) to facilitate grabbing different volumes of tissue, in different orientations, tangent or perpendicular, to the surface. Some jaws may also include a stinger 107 (FIG. 7C) to help immobilize the sample while closing the jaws. Currently, biopsy forceps may be provided by various suppliers, including, but not limited to: ABS; ASEPT INMED; MEDIGLOBE; BOSTON SCIENTIFIC; CONMED; COOK; EUROBIOPSY; LIFE EUROP PARTNERS; NET; and OLYMPUS.
As described above, optical biopsy probes are a new class of medical devices. Instead of extracting a sample from an area of interest, endoscopists may use optical biopsy probes to collect and analyze the light reflected or re-emitted by the tissue. One example of the light process is through fluorescence processes. Further, spectroscopy and imaging analysis techniques are commonly used through optical biopsy probes.
Spectroscopic optical biopsies include illuminating the tissue with a certain excitation radiation, generally in the UV range, and collecting the light with the optical biopsy probe that may be selectively remitted by the tissue. A spectroscopic analysis of this secondary radiation may then be performed. Because different molecules absorb and re-emit light differently, biological changes occurring at the cellular level during the development of a pathology may be detected and used to characterize this development. Optical fibers may transport excitation to the subject tissue and may also serve as a means of light collection. Both functions may be performed by a unique fiber, or by different fibers associated together in a fiber bundle. Excitation sources, dispersing elements, and detectors may be located outside the patient while light may travel inside the patient within the optical fibers.
Microscopic optical biopsies may include collecting the light coming from the area of investigation and forming an image instead of a spectrum. In this case, the pathology characterization may rely on the observation and identification of the microscopic changes of the tissue architecture. Images may be produced from the light scattered by microscopic heterogeneities in the tissue (reflectance microscopy) or from the light re-emitted by some fluorescence mechanism (fluorescence microscopy). In the latter case, the fluorescence may either be endogenous, as fluorescent molecules naturally exist in the tissue, or may be exogenous, because some fluorescent markers may have been delivered to the tissue.
To produce such an image, optical biopsy probes may consist of a fiber bundle equipped with distal optics to examine the tissue at different optical resolutions, fields of view, or working depths. The illumination light may either be sent through the entire bundle, or through individual fibers, sequentially. The former configuration may be regarded as a fibered version of an epi-illumination microscope. The latter configuration may be associated with a proximal scanning device which addresses each fiber successively. The complete system may therefore act as a fibered confocal microscope. Such an epi-illumination fiber based endomicroscope is marketed by Remincalm LLC. Mauna Kea Technologies markets a confocal fiber based endomicroscope, Cellvizio®.
Another process may involve a unique fiber that may be used to provide light illumination and collection. In this particular case, a miniaturized scanning mechanism may be mounted at the distal end of the fiber. Such fiber-based endomicroscope based on a microscopic distal scanner is available from Optiscan.
A fiber bundle and a distal scanner may be combined into a single unit. In these particular cases, one fiber may be used for the illumination while the rest of the bundle may collect the fluorescent light. Eric Seibel, from the HIT Lab, at University of Washington, has developed such a concept.
A large variety of endoscopic tools exist, including snares, knives, and needles. Furthermore, attempts have been made to implement a solution combining optical biopsy capability and a forceps capability. In such combinations, the fiber optics became part of the forceps mechanism. For instance, the wire, connected to the handle, which pulls on the lever or the pivot was replaced by the fiber itself. However, these solutions have been developed only for spectroscopy, and not in a configuration where distal optics were used.